Textures not showing up on objects unless selected in UV editor
I'm not quite sure what you mean, but when you say "without having to switch window layouts for every object" it sounds like you're changing window layouts, just to do the UV Mapping, which is not necessary. I'm guessing that you're using the Default layout for unwrapping and the UV Editing layout for assigning the image, and you're right to guess that there's an easier way. (this will help)

In the header of every window, there is a button all the way on the left which will let you change the window type. What you probably want is to change one window to the UV/Image Editor and another to the 3D viewport, but in the same layout. This will let you see both at the same time. (All of the layout is totally customizable; the various layouts that have names are just presets, you can even change those or add custom layouts). In fact, I usually use the Default layout and I'll change the top-right window (which is usually an outliner) to a small 3D view, and then just change the big main window to whatever I'm doing at the moment, even another 3D view.

Another problem that you might be encountering is that Blender decouples the viewport texturing from rendered texturing. The render will use the image in the material settings, but the viewport will use the image that's selected in the UV/Image Editor for that UV set. (You can have multiple UV sets on a single object, but each UV set can only have one image). This means that you can see one texture in the viewport, and a completely different one in the render. This also means that if you haven't chosen an image in the UV/Image editor, then it won't show up in the viewport, even though it will render.

Hope that helps!